By default Travis CI will use the latest dmd version. It is also possible to test projects against
gdc or ldc and to choose specific compiler versions. To do
so, specify the compiler using the d: key in .travis.yml.

Examples:

d:dmd-2.066.1

# latest dmd, gdc and ldcd:-dmd-gdc-ldc

# latest dmd and ldc-0.15.1d:-dmd-ldc-0.15.1

# dmd nightlies and beta of dmd, ldcd:-dmd-nightly-dmd-beta-ldc-beta

All valid versions from the D’s official install script are supported.
Testing against multiple compilers will create one row in your build matrix for each compiler. The
Travis CI D builder will export the DC env variable to point to dmd, ldc2 or gdc and the
DMD env variable to point to dmd, ldmd2 or gdmd.

Because project dependencies are already handled by dub, Travis CI skips dependency installation for
D projects. If you need to perform special tasks before your tests can run, override the install:
key in your .travis.yml: